This application claims the priority of German Application No. 196 41 952.2, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a fuel guidance system for an internal combustion engine having in-line cylinders and inlet bores for connector pumps and, more particularly, to a fuel guidance system with high pressure lines between the connector pumps and associated injection valves, as well as with a supply line that carries the fuel, extends over the length of the cylinder housing, and is connected with the pumps.
German Patent document DE 43 26 162 C1 (which corresponds to U.S. Pat. No. 5,411,001) discloses a fuel guidance system arranged in the cylinder housing of a multicylinder internal combustion engine. A continuous lengthwise channel arranged next to the connector pumps in the cylinder housing functions as the fuel supply. This lengthwise channel is provided with branches that communicate with associated connector pumps in the form of projecting diagonal bores.
In addition, a through flow channel is provided as a fuel return. The through flow channel runs in connecting ribs projecting laterally from the row of cylinders, said ribs connecting adjacent receptacles for the connector pumps and projecting from the long side of the row of cylinders. The fuel then returns through the through flow channel as well as through annular intermediate spaces formed by annular grooves in the connector pumps.
The separate fuel supply and fuel return require that costly deep bores be drilled in the engine block.
There is therefore needed a fuel guidance system which achieves considerable simplification with respect to the manufacture of the cylinder housing or engine block.
These needs are met by a fuel guidance system for an internal combustion engine with in-line cylinders, with receiving bores for connector pumps, with high pressure lines between the connector pumps and associated injection valves, as well as with a supply line that carries the fuel, extends over the length of the cylinder housing, and is connected with the pumps. The supply line with the connector pumps and a solenoid valve control, whose control valve controls the flow connection between the supply line and the high-pressure line, runs as a continuous fuel supply line in the cylinder housing. The supply line intersects or is tangent to the inlet bores or runs separately outside the cylinder housing. At least one feed line that connects with the supply line leads to the low-pressure side of the control valve.
Advantageous improvements on the invention are described herein.
Eliminating a deep bore in the cylinder housing considerably reduces the cost of manufacture. The only deep bore remaining, as a continuous supply line for the fuel guidance system, also simplifies the cost of the connector pump , since the latter only requires a single annular chamber as the flow connection. In addition, the sealing problem in the vicinity of the pump is at least reduced by providing only one annular chamber.
The arrangement according to the invention of a continuous supply line that runs separately next to the connector pumps, said line therefore not being provided in the cylinder housing, has the advantage that it can be made of plastic and can be made in such fashion that this separate supply line can contain electrical leads to the connector pump, such as a cable harness and connectors, as well as an overflow valve, temperature sensor, fuel filter, etc. The supply line can be made as a direct attachment for the respective connector pump.
The supply line, made of plastic, damps the control peaks of the individual connector pumps. In this way, the influence of the connector pumps on one another is considerably reduced.
The cast, high-volume, through flow suction chamber, which, when viewed in cross section, has a width that approximately corresponds to the diameter of the connector pumps, improves the quality of injection. This is because the connector pumps influence one another to a lesser degree. It also results in greater stability of injection. Moreover, improved conditions are created for implementing pre-injection.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.